These figures are for 36 by 52 inches, with 4 inches of overhang and 2 1/2 inch binding. On 42 inch fabric the backing is just past one width, which is why the yardage jumps.
Materials for a 36 × 52 inch quilt
Four inches of overhang on the back and the batting. Binding is 2 1/2 inch strips. The top is not in this list, because a pieced top is not a rectangle.
- Binding, 42" fabric
- 3/8 yard
- Backing, 42" fabric
- 2 1/2 yards
- Backing, 108" fabric
- 1 1/4 yards
- Batting to cut
- 44" × 60"
Open Backing in the studio. The form on this page is that calculator.
Fat quarters and the back
A bundle of fat quarters is a pleasant way to piece a baby top, and it is a poor way to back one. The back wants a continuous piece, or two panels sewn with one seam. Four inches of overhang makes this quilt 44 inches wide, which is just past a 42 inch bolt, so you are into a second panel unless you use wider backing cloth or a slightly smaller overhang.
If 4 inches feels generous for a quilt this small, drop the overhang to 2 in the card. The back may then fit on one width, and the batting still has room to be trimmed. The fat quarter calculator is the one for the top pieces.